Lab Safety Procedures Quiz

Disinfect bench top with lab disinfectant upon entering the lab.
Gather necessary materials, including lab manual and pencil, at the start.
Wash hands with soap and water for 20 seconds when arriving and before leaving.
Return all lab materials as directed by the instructor before exiting.
Disinfect bench top and dry with paper towels after completing the lab.
Push chairs under the bench to maintain a clean workspace.
Adhere to safety rules: always wear gloves and goggles with chemicals.
Tie hair back, do not eat or drink, maintain short nails, and wear enclosed shoes.
Stay prepared and organized for each lab session.

Aseptic techniques prevent contamination of cultures and the environment by microorganisms.
Agar is a solid growth medium made from seaweed.
Broth is a liquid growth medium, typically used for bacterial culture.
Inoculation transfers microbes between cultures.
Inoculating loop and needle are essential tools used to streak bacteria or stab into solid media.

For broth to broth: Sterilize the loop, retrieve culture, flame the tube, and withdraw a bead of culture.
For broth to agar slant: Same initial steps as broth to broth, with additional passing through and flaming the tube.
For broth to agar deep: Sterilize needle, insert into tube, and withdraw after inoculation.
Label and incubate media properly, particularly agar plates, using tape for clear identification.

Streak plates aim to isolate single bacterial cells on Petri dishes.
Pure cultures consist of a single microbe type, achieved by isolating from a single cell.

Familiarize with all microscope parts and their functions.
Calculate total magnification using the objective and ocular lens values.
- 4x → 40x, 10x → 100x, 40x → 400x, 100x → 1000x.
Key functions include magnification, resolution (detail visibility), and parfocalism (maintenance of focus).

Start with the lowest magnification (4x or 10x) for initial viewing.
Position the slide on the stage, using coarse focus to bring the specimen into view.
Center the specimen and adjust lighting before fine-tuning focus.
Switch to higher magnification if necessary, re-adjusting focus.

Simple stain: Basic dyes enhance visibility of bacterial shape and arrangement.
Negative stain: Stains the background, leaving cells clear for structural analysis.
Capsule stain: Identifies bacteria with protective capsules.
Gram stain: Differentiates bacteria based on cell wall characteristics (purple for Gram positive, pink for Gram negative).
Acid-fast stain: Identifies bacteria with waxy cell walls, visualized in red.

Gram stain steps: Crystal violet, iodine, ethanol, and safranin.
Negative stain uses nigrosine for visualization.
Acid-fast stain steps: Carbon fuchsin, heat, iodine, acid-alcohol wash, and methylene blue.
Endospore stain procedures: Malachite green, heat, rinse, and safranin.
Basic stain: Crystal violet followed by water rinse.
Capsule stain: Crystal violet and copper sulfate for visualization of encapsulated bacteria.